After suffering acute morning sickness for the past month, Kate Middleton has made her first public appearance since announcing the news that Royal Baby #3 is on the way.

Princess Kate joined her husband Prince William and her brother-in-law Prince Harry to celebrate World Mental Health Day at a special Buckingham Palace reception to honor those working in the mental health field and their Heads Together campaign which aims to reduce the stigma surrounding mental health issues.

Princess Kate’s tiny baby bump was caught on camera during the event, and tweeted out for everyone to see.